1. Field of the Invention
This disclosure relates to the non-invasive application of ultrasonic energy to enhance and/or accelerate the process of wound healing, and more particular, to the healing of wounds including ulcers, such as venous ulcers.
2. Description of the Related Art
Venous ulcers on human legs have proven difficult to treat, for example, because of the lack of vascularization in and around the wound.
The term xe2x80x9cwoundxe2x80x9d for the purposes of xe2x80x9cwound healingxe2x80x9d, as used throughout the present disclosure, includes ulcers such as venous ulcers as well as burns, ulcerated wounds due to, for example, diabetes, surgical incisions or other surgical cuttings including stitched surgical cuttings, skin grafts, hair transplants, re-vascularization, bed sores, tissue dehiscence, and ligament and tendon repair and reconstruction. In general, as used throughout the present disclosure, the term xe2x80x9cwound healingxe2x80x9d encompasses addressing damage to, repair of, or restoration of soft tissue.
U.S. Pat. No. 4,530,360 to Duarte (hereafter xe2x80x9cDuartexe2x80x9d), describes a basic therapeutic technique and apparatus for applying ultrasonic pulses from an ultrasonic applicator placed on the skin at a location adjacent a bone injury. Duarte gives a range of radio frequency (RF) signals for creating the ultrasound, ultrasonic power density levels, a range of duration of each ultrasonic pulse, and a range of ultrasonic pulse frequencies. The length of daily treatment is also described in Dart. The Dart patent is incorporated herein by reference.
U.S. Pat. Nos. 5,003,965 and 5,186,162, both to Tallish and Lifshey (hereafter xe2x80x9cTallish ""965xe2x80x9d and xe2x80x9cTallish ""162xe2x80x9d, respectively) describe an ultrasonic delivery system in which the RF generator and transducer are both part of a modular applicator unit which is placed at the skin location. The signals controlling the duration of ultrasonic pulses and the pulse repetition frequency are generated apart from the applicator unit. Tallish ""965 and Tallish ""162 also describe fixture apparatus for attaching the applicator unit so that the operative surface is adjacent to the skin location. In one application described in Tallish ""965 and Tallish ""162, the skin is surrounded by a cast.
U.S. Pat. No. 5,211,160 to Tallish and Lifshey (hereafter xe2x80x9cTallish ""160xe2x80x9d) also describes a fixture apparatus which is mounted on uncovered body parts; i.e. without a cast or other medical wrapping. Tallish ""160 also describes various improvements to the applicator unit. Each of Tallish ""965, Tallish ""162, and Tallish ""160 is incorporated herein by reference.
U.S. Pat. No. 5,755,746 to Lifshey and Talish (hereafter xe2x80x9cLifshey ""746xe2x80x9d); U.S. Pat. No. 5,626,554 to Ryaby, Talish and McCabe (hereafter xe2x80x9cRyaby ""554xe2x80x9d); U.S. Pat. No. 5,556,372 to Talish, Ryaby, Scowen and Urgovitch (hereafter xe2x80x9cTalish ""372xe2x80x9d); and U.S. Pat. No. 5,520,612 to Winder, Talish and Ryaby (hereafter xe2x80x9cWinder ""612xe2x80x9d), entitled Locator Method and Apparatus, Gel Containment Structure, Apparatus for Ultrasonic Bone Treatment, and Acoustic System for Bone-fracture Therapy, respectively, provides ultrasonic apparatus and methods which are applicable to wound healing. Lifshey ""746, Ryaby ""554, Talish ""372, and Winder ""612 are incorporated herein by reference.
In general, an ultrasound carrier frequency between 20 kHz and 10 MHZ coupled with a relatively low-frequency modulating signal, such as 5 Hz to 10 kHz, and a spatial peak temporal average acoustic intensity, such as an intensity less than about 100 milliwatts/cm2, should aid in and should be effective in wound healing.
Heretofore, such techniques have not been applied to heal wounds by internal application of ultrasound, such as using reflection of ultrasonic waves by reflection from internal tissue such as bone.
It is herein recognized that both longitudinally propagating ultrasound and shear waves generated by a transducer mechanism and/or by such longitudinally propagating ultrasound provide effective healing of wounds.
A portable therapeutic device and method of use thereof for healing a wound includes a transducer having an operative surface, with the transducer, disposed substantially adjacent to the wound to emit ultrasound to propagate in the direction of the wound for the healing thereof. Reflections of the ultrasound by bone tissue and by skin layers propagate toward the wound as longitudinal waves for the healing thereof, and shear waves are generated by the longitudinal waves and/or the reflected longitudinal waves for the healing of the wound.
The transducer may include an axis and a focusing element for focusing the propagation of the ultrasound at a predetermined angle with respect to the axis, with the focused ultrasound propagating toward the wound for the healing thereof.
Alternative configurations of the operative surface of the transducer include an annularly shaped operative surface for emitting the ultrasound therefrom, with the wound encircled by the operative surface for receiving the ultrasound and/or reflected ultrasound.
A housing may be provided for positioning the transducer substantially adjacent to a portion of the skin substantially adjacent to the wound, and for causing the portion of the skin to form a cavity, with the operative surface of the transducer disposed in the cavity to emit the ultrasound to an internal surface of the wound for the healing thereof.
Reflective media may be internally disposed within the body having the wound for reflecting the ultrasound from the transducer to propagate toward the wound for the healing thereof. Fixture structures, extending about a portion of the body having the wound, may also be provided for positioning the transducer substantially adjacent to the skin substantially adjacent to the wound. The fixture structure may include an adjustable strap.
In other embodiments, the transducer may be a rod-shaped operative surface having an axis for emitting the ultrasound radially toward the wound for the healing thereof.
Using the disclosed therapeutic devices, wounds are safely and simply treated, with such wounds as venous ulcers responsive to therapeutic ultrasound to be healed effectively. Such therapeutic devices and methods of use provide for wound treatment by modest adaption of existing devices for delivering ultrasound in therapeutic settings.
In one embodiment, a device is provided for delivering an ultra-high-frequency carrier signal for low power excitation of an acoustic transducer which is acoustically coupled to a limb or other part of a living body. The transducer is positioned adjacent an external skin location in the vicinity of the external border of the wound on the skin to provide a surgical, non-invasive transcutaneous delivery of at least part of its acoustic energy directed from the external skin location toward a portion of a bone located within the body in the vicinity of the boundary of the wound internal to the body. The boundary of the wound internal to the body is also referred to herein as the internal or interior surface of the wound.
Once the acoustic energy enters the body, it passes into internal body tissue and/or fluids. The acoustic energy, in the form of ultrasonic pulses, is reflected off the surface of underlying bone or other ultrasound reflective material, and the reflected ultrasound travels toward at least part of the internal surface or underside of the wound. Healing of the wound at the internal surface by the generation of epithelial cells is enhanced via the acoustic stimulation.
Preferably, a low frequency signal which is present as a modulation of the carrier frequency is transmitted from the ultrasonic transducer, through interposed soft tissue, and onto the surface of the bone. The carrier wave incident on the bone surface, or other reflection surfaces in the body, is reflected toward the internal surface of the wound. When the carrier wave impinges the internal surface of the wound, at least a portion of the carrier wave is converted into therapeutically beneficial shear waves of acoustic energy, flooding a region of the internal surface of the wound. The shear waves increase vascularization at the internal surface of the wound, thus enhancing growth of epithelial cells. The epithelial cell growth represents healing of the wound. The technique thus promotes healing of the wound from the internal surface of the wound.
The number, position, and size of ultrasonic applicators used at the external skin location are chosen based on the size and position of the wound, and the relative position and proximity of the bone from which the ultrasonic waves are reflected. One or more ultrasonic therapy treatments per day, each having a duration of approximately 20 minutes, is suitable.